[mickenordin]

Hi,
I have an old Terco CNC benchmill which I am about to replace the old control unit to a EMC2 control and new drivers.
These are the existing stepper motors:
X/Y-axis:
Sanyo Step-Syn 103-807-7 (6-wire) NEMA 34
Step: 1,8 degree/step
Data: 1,8V and 4,8A

Z-axis:
Sanyo Step-Syn 103-815-2 (6-wire) NEMA 34
Step: 1,8 degree/step
Data: 2,5V and 4,6A
I don't know the inductance etc for the steppers.

Mill motor:
Marked as 0,180kW 0-190 DCV motor (looks more powerful than 180W though). Guess I need a 0-10V controlled driver or similar for this one.

Question:
Is it possible to retrofit with G540 and keeping the existing steppers?
If not, whats other options (other steppers,other drives,kits) is suitable?

Thanks in advance,
/Micke

[acondit]

Micke,

The G540 is limited to 50v and 3.5 amps. You need to verify that the ratings on your motors are unipolar ratings. If so, you could use the G540, connect your motors either half winding or full winding, with appropriate current settings for those configurations (up to a max of 3.5 amps).

However, I seem to recall that Mariss or Marcus recommended against using the G540 with Nema 34 motors. You need to find the inductance ratings of your motors to calculate an appropriate voltage for those motors.

Take a look at the Gecko G203 as one possible drive to use with the existing motors. Also take a look at the new motors that Homeshopcnc and Keling for use with the G540. I suspect that price wise, new Nema 23 motors and the G540 would give you adequate performance at a better cost than G203 drives with the old motors.

However, you really need to figure out how much force you need to drive the mill at the speeds you want to run in order to make an intelligent decision though.

Alan

[mickenordin]

Thanks Alan,
I've measured the steppers and the windings have the following static resistance:
X/Y= 0,4 Ohm
Z = 0,5 Ohm
and are connected like this (x/y motor):

Wire: 1 5
_I_ _I_
/ \ / \
Ohm 0,4 0,4 0,4 0,4
I I I I
I I I I
Wire: 4 6 2 3

Can you tell from this if these are unipolar steppers and also the rating?
How can I find out the inductance for these motors?
I've searched for the spec's on the net without success.
I understand that if the motors are of low inductance they are good enough
to keep and to put the money on the drivers, but if they are high inductance it's better to replace both.
Anyone who knows where to find the specs?
/Micke

[mickenordin]

Got strange format after posting.
Winding connections are:
1 - winding - 4
1 - winding - 6
5 - winding - 2
5 - winding - 3
/Micke

[acondit]

Thanks Alan,
Can you tell from this if these are unipolar steppers and also the rating?
How can I find out the inductance for these motors?
I've searched for the spec's on the net without success.
I understand that if the motors are of low inductance they are good enough to keep and to put the money on the drivers, but if they are high inductance it's better to replace both.
Anyone who knows where to find the specs?
/Micke

6 wire motors are unipolar steppers and 8 wire motors can also be used as unipolar. However, 4, 6 and 8 wire motors can all be used as bipolar. Mariss said that the unipolar rating is 1.41 times the series rating. So 4.6/1.41 = 3.26 amps, 4.8/1.41 = 3.404 amps. So you should be able to run them with the G540. The real question is what voltage would be optimum. Mariss has published a formula for max voltage but it requires that you know the inductance of the motors. SQRT(Inductance)*32 = Voltage

I have a sanyo denki spec sheet but it doesn't list your motors. My guess is that they are older ones. Still you might be able to find the info about them on the web. Or you might just ask Mariss he always seems to have unbelievable amounts of data at is fingertips or in his head.

Alan

[mickenordin]

Thanks Alan,
I've sent a email to Mariss about this.
Will post the answer if someone else might have similar questions.
Br,
/Micke

[AMTB]

Hi
i also build CNC controller PC based. my system robust and durable. best part of my controller is that i used only generic components that are less expensive and simple to use, and also that i used commercial size AC servomotors and drives.
Some info about my system AMTB

thanks
Aram